Water worldwide

Every known form of life on our planet depends on water. It is a vital part of many metabolic processes within the body. Significant quantities of water are used during the digestion of food.
About 72% of the fat-free mass of the human body consists of water. To function properly, the body requires between one and seven litres of water per day to avoid dehydration, the precise amount depending on the level of activity, temperature, humidity, and other factors. Water is lost from the body in urine and faeces, through sweating, and by exhalation of water vapor in the breath.
Humans require water that does not contain too much salt or other impurities. Water that is suitable for drinking is termed potable water. Because of the growth of world population and other factors, the availability of drinking water per person is shrinking.

A rare resource

Water is a strategic resource for many countries. Many battles and wars, such as the Six-Day War in the Middle East, have been fought to gain access to it. Experts predict more trouble ahead because of the world's growing population, increasing contamination through pollution and global warming.
UNESCO's World Water Development Report (WWDR, 2003) from its World Water Assessment Program indicates that, in the next 20 years, the quantity of water available to everyone is predicted to decrease by 30%. 40% of the world's inhabitants currently have insufficient fresh water for minimal hygiene. More than 2.2 million people died in 2000 from diseases related to the consumption of contaminated water or drought. In 2004, the UK charity WaterAid reported that every 15 seconds one child dies due to water-related diseases that could easily be prevented.

Water for everyone?

There are three ways to improve the availability of drinking water: produce it more, distribute it better to the needy, and waste it less.
Drinking water is often collected at spring or extracted from artificial borings in the ground, or wells. Building more wells in adequate places is thus a possible way to produce more water. Other water sources are the rain or the seas. This water however is not adequate for human consumption, and water purification is needed. Popular methods for purifying water are filtering, boiling and distillation. More advanced techniques exist, such as reverse osmosis.
The distribution of drinking water is done through municipal water systems or as bottled water. Governments in many countries have programs to distribute water to the needy at no charge. Others argue that the market mechanism and free enterprise are best to manage this rare resource, and to finance the boring of wells or the construction of dams and reservoirs.
Reducing waste, i.e. using drinking water only for human consumption, is another option. In some cities, such as Hong Kong, sea water is extensively used for flushing toilets citywide in order to conserve fresh water resources. Polluting water may be the biggest single misuse of water; to the extent that a pollutant limits other uses of the water, it becomes a waste of the resource, regardless of benefits to the polluter.